@EventHandler(display = true)
 protected void onFeatureChange(FeatureEvent ev) {
   if (!viewer.getTable().isDisposed()) {
     // XXX this tries to preserve selection; this is index based; it causes
     // a selection event; if sort has changed, another element ist selected!
     viewer.refresh();
   } else {
     EventManager.instance().unsubscribe(this);
   }
 }